Selection of potential probiotic Lactobacillus strains of human origin for use in dairy industry

In the present study, phenotypic and genotypic methods and MALDI-TOF mass spectrometry were applied for the species identification of 29 out of 30 strains of the genus Lactobacillus isolated from faecal samples of 30 breastfed infants. All strains were tested for growth in milk and/or reconstituted skimmed milk supplemented with 0.5 % yeast extract, production of lactic acid, bile salts and low pH tolerance, and for production of beta-glucuronidase. PCR screenings of tyrosine-decarboxylase and histidine-decarboxylase genes were also carried out. Survival of Lactobacillus cells at low pH and their bile tolerance were strain specific. Finally, seven strains of probiotic species were selected for possible use in the dairy industry and for further tests concerning their probiotic characteristics.